Paper cup and method for the manufacture thereof



March 18, 1941. 5; AMBERG 2,235,349

J PAPER CUP AND METHOD FOR THE MANUFACTURE THEREOF Filed May 6, i939 IN VENTOR.

ATTORNEY.

Patented Mar. 18, 1941 PATENT OFFICE PAPER CUP AND NIETHOD FOR THE MANUFACTURE THEREOF Ralph G. Amberg, Libertyville, Ill., assignor to Universal Paper Products Company, Chicago, 111., a. corporation of Illinois Application May 6, 1939, Serial No. 272,080

71 Claims.

This invention relates to the manufacture of paper cups and more particularly paper cups of the type described in United States Patents Nos. 2,056,893, 2,139,613'and 2,139,614, all granted to Walter E. Amberg. The invention is especially concerned with the production of an improved type of cup by a new and improved method by which the cup is formed from a continuous strip of paper.

The type of cup described in the aforementioned patents is made-practically entirely without waste, and therefore, it is one of the most economical cups ever developed. An important feature of the manufacture of this cup, as pointed out in United States Patents Nos. 2,139,613 and 2,139,614, resides in the fact that the cup is formed from a continuous strip of paper. Usually cone-shaped paper cups having a pointed apex are made by forming initially a paper blank and subsequently rolling or winding the blank thus formed into a conical vessel. In most instances it has been necessary to die-cut blanks from paper and stack them one upon another in a magazine from which they are fed singly to a pair of cup forming cones.

In other-instances it has been proposed to cut the blanks from a continuous strip of paper or web and to feed the blanks thus cut singly one by one to cup forming cones. In all of these in- 3 stances it has been customary to have a certain amount of waste which is produced during the die cutting, the blank forming or the cup forming operations. In the first of these instances the waste results from the paper between adjacent die cuts, in the second, by the paper which is disposed between adjacent cup blanks and'is rejected as surplusage, and in the third by the excess paper which is trimmed from the blank by means of a knife engaging with the base of one of the cones.

40 In making paper cups of the type covered by the patentspreviously mentioned and according to the methods described therein, all waste may be eliminatedand at the same time every portion of the paper is used in forming and reinforcing the cup. For convenience it is sometimes desirable to cut off sharp ends of the paper strip prior to or during the cup forming operation but the amount of paper thus lost is negligible from the practical point of view.

One of the problems encountered in the forma-. tion of paper cups of the type described is the proper formation of the apex of the cup in order to render the cup entirely leakproof. It will be observed, for example, in considering United States Patent No. 2,139,614,.that a continuous strip of material adapted to be formed into a series of cups in succession is advanced to a forming mandrel in such a way that the forming operation begins in proximity to the leading edge of the material or more specifically, at the center 5 ,of radius of curvature of that portion of the cup which is to form the mouth. The forming mandrel in this particular operation rotates around its own axis and also in an orbit, and in so doing presses against a smooth fixed surface which 10 serves as a pad or presser plate during the operation of forming the cup. Each time the mandrel rotates in its orbit a cup is formed and discharged and at the time the mandrel discharges the cup, the paper strip advances again to be in position 15 for another forming operation. When it is realized that this cup forming operation may take place at speeds from to 250 cups per minute, or even higher, it will at once be understood that the problem of properly forming the apex be- 20 comes extremely important.

Various types of instrumentalities may be used to feed the paper strip to-the forming cone, the feed being either continuous or intermittent. Many types of devices maybe employed to assist 25 the feeding operation.- Likewise, a number of different devices may be employed to assist the formation of the apex of the cone, but from every standpoint it is desirable to have the machine as simple as possible. At the same time it is desira- 30 ble to form the cups in such a way that leakage is practically out of the question. v

With the foregoing considerations in mind, one of the objects of the present invention has been to provide a new and improved type of paper cup having a leakproof apex.

Another object has been to provide a paper cup of the character described in which the apex is formed accurately, conveniently and simply.

Still a further object is to provide a method of forming paper cups having an improved leakproof apex which is extremely simple in operation and simplifies rather thancomplicates the cup forming machine. Other objects will appear hereinafter. 45

\ According to this invention it has been found that in making cone-shaped cups havingan apex from material so shaped that opposite sides have the same radius of curvature, one of saidsides being convex and the other concave, the simple 50 expedient. of forming a slit in the leading or concave edge of the material prior to or, if desired,

during the operation, leads to the production of a new and improved type of cup in which the apex is capableof remaining leakproof even when a 5 liquid is allowed to stand in the cup over a long period of time. This is particularly true, for'example, of cups which are used as soda cups, although the accuracy ,with which the apex is formed is also important in connection with ordinary drinking cups. Y

- The method involved is particularly well adapt-' ed for use in connection with the formation of cone-shaped cups having a pointed apex where a strip of material from a continuous roll is advanced to a conical former in such a manner that the forming operation begins from the leading edge of said material. According to this invenforms a slit in the leading edge for the next cup forming operation.

The slit thus formed in the forward edge of the strip of paper is usually spaced a substantial distance from the apex of the cup or the center of the mandrel orbit and is on that side of the apex from whence the cup forming operation is begun. The mandrel is provided with means for holding the paper against it as it rotates in -contact therewith. Thus, according to a preferred method of operation, as a cone-shaped mandrel rotates about its ownaxis and in an orbital path, it picks up the leading edge of the paper, thereby beginning to wind the paper into the form of a cone. As the winding ration continues the cutting edge of the ma drel severs the paper along a path transversely ,of the longitudinal axis of the paper. The gripping means whereby the paper is gripped to the mandrel is normally placed adjacent the base or outer portion of the mandrel. During the initial stages of the winding operation the portion of the paper adjacent the gripping means will be held closely against the mandrel but the slit in the leading edge of the paper causes that portion of the paper adjacent the slit and particularly. that portion of the paper between the slit and the apex point to fly outward and be more or less free from the mandrel. Prior to or during the forming operation an adhesive is applied to a face portion of the paper strip which is ultimately to form an to roll in its orbit and thus, firmly seals the flap in an area adjacent the apex portion of the cup,

eration and during the time that the cup is being discharged, the paper strip'is brought into position for the next forming/ operation. One of the features of this invention is to be found-in the fact that the whole operation of sealing the apex in the manner described is accomplished by forming a slit in a paper strip at predetermined intervals and without the necessity for using any,

other instrumentalities whatsoever. The speed of operation is not decreased. Furthermore, by using a method of this type it has/been found that certain devices heretofore employed to as-.'

sist the advancement of the paper can be discarded, thus simplifying the machine and decreasing the cost of operation.

Other features and advantages of the invention will become apparent from a reading of the following specification in the light of the accompanying drawing, in which:

Figure 1 is a top plan view illustrating some what diagrammatically the method of the present invention;

Figure 2 is a view of the cup being wound upon the former of Figure l;

Figure 3 is an enlarged cross-sectional view taken through line 3-3 of Figure 2 Figure .4 is a view in section of the cup former and cutting knife;

Fi e 5 is a side elevational view of the completed cup;

Figure 6 is a plan view of the cup shown in Figure 5;

Figures 7 and 8 are views in section taken through 1-1 and 8-8 of Figure 5, respectively: Figure 9 is a plan view of the apex portion of the cup unwound to show the position of the creases and silt;

- Figure 10 is a view in perspective of the apex of the cup partially formed as in Figure 2; and

Figure 11 shows a modifiedform of blank. In the drawing the machine and method are purposely shown somewhat diagrammatically.

The actual machines which have been constructed to embody the present invention contain many details of design and construction which are sub ject to much variation and which although useful are not considered patentable and hence, are not being disclosed or claimed herein. On the Y contrary, only the basic important and broadly novel features of the invention are disclosed and claimed inorder that the importance of such features will not be obscured or overshadowed by the inclusion of mere details of feeding mechanisms, gluing devices, gear arrangements, supports, stackers and the like. .All of these latter named instrumentalltles are old and exist in many different forms so that any mechanic skilled in the art can quickly and conveniently adopt and adapt them for the practice of this invention.

Turning now to Figure 1, a continuous strip of paper II coming from a roll or other suitable source of supply is fed by a suitable mechanism to a forming cone II. In actual operation the forward or breast edge I of the paper strip is fed into the position illustrated in Figure 1 in which apex point I. in proximity to the center of edge ll coincides with the apex of the former I 2 and when it reaches this point the former rolling over, the end of the paper strip causes further feed of the paper to be temporarily suspended while a cup rolling or winding operation takes place.

The conical cup former l2 rotates about its own axis and simultaneously moves through a circular orbit of which, in the construction 11- lustrated in Figure 1, the axis of the cone forms the center. .In the position illustrated a mechanical latch or clamp ll, known in the art as a pick-up, engages the forward extremity 2| of the Paper strip and as the mandrel continues to rotate and move bodilyin its circular path, the forward end of the strip is wound around the strip II! from being torn and twisted it is necesf sary to sever the cup from the end of the strip and this is done simultaneously with the cup forming operation.

As shown in Figure 4, the rear edge 22 of conical former I2 is sharpened to serve as a cutting edge and it cooperates with'a cutting edge 24 formed on the forward extremity of a platform 26 across the upper surface of which paper strip I is fed. The contour of cutting edge 22 is arcuateand corresponds identically to the path followed by the cone edge during the course of its. operation about the table or smooth surface upon which the cone shaped former I2 is mounted. As the cup is completed it is stripped from conical former I2 by any convenient stripping device such as compressed air, a movable tip or plunger forming the apex of the conical former,

or a stripping wheel which engages the exterior" of the cup. The glue lines a, b and c may be I applied to, the paper strip at any convenient point with any suitable type of gluing mechanism such as applicator rolls.

The essential feature of the present invention resides in the provision of the slits 28, 30, 32 and 34 at predetermined intervals in paper strip ID, as shown in Figure 1. These slits are'so placed that they intersect the line of severance of cutting edge 22 with paper strip l0. Thus, as shown in Figure 2, when mandrel l2 has partially completed its orbital path and has partially formed a paper cup, slit 28 has caused a portion 36 of the leading edge of the paper to separate from the body of the paper cup and extend outwardly. This outwardly extending portion or flap 36 becomes sealed by means of glue line 0 across the upper face of the paper and is thereafter overlapped by overlapping portion 38, whereby the flap 36 is sealed within theoverlapped seam. It will be observed that the winding operation causes a reverse crease 50 to be formed between the apex point and the innermost extremity of the slit, as shown in Figures 3, 9 and 10. By a reverse crease is meant a crease in which the face of the flap is bent backward or reversed with respect to the face of the strip. A regular comes into contact with the interior of the cup.

This offset should be large enough to take care of the space created by pocket portion 36. In I order toadd to theattractiveness of the cup, the ends of the paper at points 44 and 46 may be severed in any suitable manner, thus producing an effect as shown in Figure 3. It will be observed thatfiin Figure that part of the leading edge of the strip between point 44 and slit 28 is represented by reference numeral 48, this edge being on'the inside of the cup.

According to the modification of the inven-- tion shown in Figure 1, the line A-A forms the central axis of the strip and is also a line joining the centers of radius of curvature of the arcs along which the strip is transversely severed. Thus, point which forms the apex of the cup,

falls on line AA and the corresponding point in each succeeding cup will also fall on line A-A. It is not essential, however, that the line AA correspond to the central axis of the strip, nor that the shape of the blank which is ulti mately to be formed be exactly as shown in Figure 1. For instance, the edge of the strip at which the forming operation is started-may correspond to line BB, the other edge remainingjust as shown in Figure 1, or the edge of the strip BB. If a cup were to be unrolled after it has been formed, as described in Figure 1, it would be found that the shape is that of a four-sided figure, two sides being curved and two sides straight, whereas, if either edge of the paper is extended to the line CC or to the line BB, but not both, the shape of the figure from which the cup is formed would be a three-sided figure,

two sides curved and one straight, and if both edges are extended to linesC-C and BB, the shape of the cup is a two-sided figure with both,

sides curved. The shape of the. material from which the cup is formed is preferably such that opposite sides have'the same radius of curvature, one of said sides being convex and the other concave with the concave side containing a slit,

cut or other line of severance. It will be understood, however, that the invention, in its broader aspects, is not limited to the formation of cups of this particular type. For example, a similar cut or slit may-be made in the lower edge of the rectangular blank shown in United States Patent No. 1,434,934, granted to Van Sant Novemher 7, 1922.

The slit, cut or other line of severance on the forward edge preferably extends in a longitudinal direction with respect to the .paper strip, although it may extend in other directions just so long as the effect of the slit during the forming operation is to permit a portion of the forward edge to separate in such a manner that the separated portion or flap is sealed face to face against an overlapping portion of the paperin the manner previously described.

The slit or partial severance of the paper strip as described in accordance with this invention may be at different points on the leading edge, or in that portion of the paper which is ultimately to become the leading edge. This will vary somewhat depending upon the desired size of the pocket portion at the apex of the cup and the size is controlled by the depth of the slit and by its distance from the apex point of the cup. Naturally with a larger sized cup a larger slit and a larger sized sealed flap portion may be formed adjacent the apex. The slit need not be severed in a single line but may be wedge-shaped or any other convenient shape. For example, as shown in Figure 11, the cut or severed portion 28 in the forward edge of the blank may have a rounded inner extremity to prevent tearing with cerausimilarpurpose and. to otherwise assist the formation of the crease, the table or surface upon which the. cone-shaped former is mounted tain types of paperwhen the cup is wound. For

may be provided with a slightly raised portion where the reverse crease is to be formed designed to complementally fit into and coincide with a hollow or dished out portion on the face of former l2, not shown. Many other variations may be made in the method described without departing from the invention.

This invention makes it possible to great rapidity a new and improved type of paper cup which is leakproof in every respect. As previously indicated, this type of cup is especially useful in the larger sizes of cups such as are employed as soda cups. In this type of cup the tendency to leak is unusually great because it is often customary to allow liquids to stand in such cups over a long period of time.- In many instances special glues are required in order to keep a cup of this type from springing a leak at the seams, but in a cup made according to the present invention, the ordinary types of gluesemployed in the manufacture of paper cups may be used. It will be appreciated that this type of cup is extremely economical to manufacture.

' Not only can the cup be made without special attachments on the machine, but also the method of making it'is such that certain attachments heretofore employed can be eliminated. For instance, among thev attachments which can be eliminated are those attachments which are used to insure that the paper is fed to the forming mandrel at the proper time. With the present method of manufacture, the apex of the cup is formed accurately prior to the completion of the forming operation and the speed of the mandrel may be so coordinated with the continuous feed of the paper that no attachments are necessary to see that the paper is fed to the proper position in the mandrel orbit. Thus, the paper may be fed continuously from a roll and as the leading edge reaches the position shown in Figure 1, it will be picked up by the mandrel and the mandrel itself rolling over the paper will stop the forward strip where the cup. is formed on the end of the strip and simultaneously severed as it isbeing wound, thereby avoiding the separate formation and handling of blanks. This is possible by vir-- tue of the fact that the end portion of the strip retains its same relative position with respect to the remainder of the strip as it is being wound. The invention can also be employed, however, in cup forming operations where a blank is first foimed 'In this instance, the slit is made as already described in the forward-edge of the blank which may be straight or curved. The blank may be severed transversely fgmi a strip already containing the slits at predeterminedintervals, or

the blanks may be formed and then slit. Other materials besides paper may be employed, for

example, regenerated cellulose, cellulose acetate,

etc.

severance extending to the apex point of the cup but this type oi 'cut'or line of severance would form with' .of a reverse crease between the point of ter- 'cups on the end of a continuous strip. Furthermore, it is of outstanding importance in the present invention that the reverse flap caused by the cut in the edge of the material be sealed to the face portion of the material as the cup is wound,

whereas the flap or-wing in the above mentioned patent is said to be provided to prevent slippage.

and is not sealed to the blank.

Having thus described the invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. That improved process of making a coneshaped vessel having a pointed apexwhich consists in forming the vessel by winding it upon the end of a continuous strip of paper, progressively severing the vessel from the end of said strip of paper as it is being wound, and partially severing the leading edge of said strip by a line of severance terminating in the interior of the strip thereby to cause a separation of said leading edge and the formation of a reverse crease in the body -of the strip prior to completion of the winding operation.

2. That improved process of making a coneshaped vessel having 'a pointed apex which consists in forming the vessel by winding it upon the end of a continuous strip of sheet material, progressively severing the vessel from the endof said st'rip as it is being wound and partially severing the edge of said strip where the forming operation is initiated by a line of severance terminating in the interior of the strip thereby to cause a separation of said edge and the formation of a reverse crease in the body of the vessel prior to completion of the winding operation. I

3. That improved process of making. a coneshaped vessel having a pointed apex which consists in forming the vessel by winding it upon the end of a continuous strip of sheet material, progressively severing the vessel from the end of said strip as it isbeing wound and partially severing the edge of said strip where the forming operation is initiated by a line of severance ter-' minating m the interior of the strip thereby to cause a separation of said edge and the forma-,

tion of a reverse crease in the body of the vessel prior to completion of the winding operation, said line of severance being so positioned that the reverse crease runs from the interior point of termination of the line of severance to the apex point of the vessel. I

4. That improved process. of making a coneshaped vessel having a pointed apex which consists in forming the vessel by winding it upon the end of a continuous strip of paper, progressively severing the vessel from the end of said strip of paperas it is being wound and partially severing the forward edge of said strip by a line of severance beginning ofiaid forward edge toward the side of the strip where the winding opera assuagetion is initiated and terminating in the body of the strip at a substantial distance. from the forward edge and at a point farther back on the strip than the apex point oi the vessel.

5. That improved process'oi making a coneshaped vessel having a pointed apex which consists in forming the vessel by winding it upon the end oi a continuous strip of material, progressively severing the vessel from theend of said strip as it is being wound and partially severing said strip by a line -of severance beginning on the edge where winding of the vessel is initiatedand terminating in the interior of the strip thereby causing a separation of said edge and the formation of a reverse crease in the body of the vessel prior to the completion of the winding operation. l

6. That improved process of making a coneshaped vessel having a pointed apex which conslsts'in forming the vessel bywinding it upon the end of a continuous strip o't material, progressively severing the vessel from the end of said strip as it is being wound, partially severing the edge of said strip where the winding oi the vessel is reverse crease-in the body of the vessel prior-to the completion of the winding operation. said're.

'verse crease in part defining a sealing ilap'adjacent the apex. point or the vessel and applying an' adhesive on said strip in an area such that the race or said flap is sealed to the face of the strip in the later stages of the winding operation. e

7. That improved process of making a cone- I vals on the side of the strip from which the w'ind-- ing operation is commenced. said out; being so positioned that the line oi severance oi the vessel from the end of the strip intersects the for .ward end of successive cuts.

Remix 0. amend. 

